THIS invention relates to a device for drawing blood.
Conventional devices for drawing blood include a vial having a synthetic rubber stopper. The vial is supplied with a lower internal pressure than ambient pressure and is commonly referred to as a vacuum vial or a Vacutainer.
Generally, the vacuum vial is used in conjunction with a holder defining a socket for receiving the vial. The holder also defines an opening for receiving a needle arrangement having an inner, hollow needle which is arranged to extend into the socket and an outer, hypodermic needle which is arranged to extend outwardly from the holder, the inner and outer needles being connected so as to be in fluid communication with one another.
To draw blood, the point of the hypodermic needle is introduced into a patient""s vein, and thereafter the vacuum vial is inserted into the holder socket so that the inner needle puncture the vial stopper. When this occurs, the pressure differential across the needle arrangement due to the relatively low pressure in the vacuum vial causes blood to be drawn through the needle arrangement and into the vial.
Various protective coverings for the hypodermic needle are available to protect users from needle stick injuries. For example, WO 91/08787 discloses a finger guard which is arranged to cover a hypodermic needle on a needle arrangement so that a user""s hands are protected during connection of the needle arrangement to a holder or disconnection of the needle arrangement from the holder. U.S. Pat. No. 5,295,972 also discloses a finger guard for a hypodermic needle. In this case, the finger guard includes an end cap with an off-centre opening for preventing the point of the needle from inadvertently becoming exposed.
A problem associated with conventional devices for drawing blood is that the holder is used over and over again while the needle arrangement is used only once. Accordingly, each time blood is drawn from a patient, a needle arrangement has to be connected to a holder and subsequently disconnected from the holder. Apart from taking time, the disconnecting of the needle arrangement from the holder after drawing blood from a patient involves the risk of a needle stick injury even where a protective cover is used.
Furthermore, since the scan holder is used over and over again, it is possible for blood in one sample to be contaminated by blood from another sample.
According to the invention there is provided a device for drawing blood including:
a disposable holder which defines a socket for receiving one end of a vacuum vial and which includes an inner needle-receiving formation projecting into the holder and an outer needle-receiving formation projecting outwardly from the holder, the inner and outer needle-receiving formations being in fluid communication with one another, characterised in that
the inner and outer needle-receiving formations are incorporated into the holder during manufacture so as to form a permanent part of the holder;
a hollow needle is connected to the inner needle-receiving formation so as to extend into the socket for puncturing a stopper on the vacuum vial when the vial is inserted into the socket;
a hypodermic needle is connected to the outer needle-receiving formation so as to extend outwardly from the holder; and
a safety cover is provided for the hypodermic needle, the safety cover including a cup having an off-centre opening through which the point of the needle can pass, and a resilient member for holding the cup over the point of the needle when the needle is inoperative.
The resilient member of the safety cover may comprise two limbs which extend along the length of the hypodermic needle and which are arranged to bias the cup into a position in which it covers the point of the needle. In this case, the hypodermic needle can be expressed for use by threading the point of the needle through the off-centre opening in the cup and drawing the cup back over the needle. When the safety cover is released after use, the resilient limbs automatically carry the cup back into the position in which it covers the point of the needle.
In one embodiment of the invention, the inner and outer needle-receiving formations are formed integrally with the holder.
In another embodiment, the holder is formed from two parts and the needle-receiving formations are integral with only one of the parts.
The needle-receiving formations may be designed to form a friction fit with the needles.
Typically, at least one of the needles is connected to its needle-receiving formation by means of a Luer Slip or Luer lock attachment.
In a preferred form of the invention, a resilient, synthetic rubber sheath is arranged to cover the inner needle when this needle is inoperative.
The inner needle-receiving formation may include a bore for receiving a portion of the inner needs. In this case, the inner needle-receiving formation may have a head for engaging one end of the synthetic rubber sheath for covering the inner needle.
Preferably, the holder includes a series of gripping ribs on the outer surface thereof to facilitate the handling of the device.